Description:

1) To advance fundamental knowledge of atmospheric transformation
of organic hazardous air pollutants. Initially, 1,3-butadiene, aromatics and epoxides will be
studied; in subsequent years this will expand to other HAPs. (2) To include the large variety of
organic HAPs in modern air quality models by extensions of the newly developed "morphecules"
concept. (3) To design and prepare a HAPs mixture for testing HAPs behavior in an urban-like
environment and for evaluating the allomorphic/morphecule representation and other
mechanisms for air quality models. (4) To perform risk calculations for the purpose of comparing
the potential cancer and noncancer risks of the reacting precursors and products in our urban-like
outdoor reaction chambers.

Approach:

The approach will be to identify and quantify reaction intermediates and products
from atmospheric transformation of select HAPs by applying newly developed analytical
techniques, which include identification and detection of aldehydes and ketones by their PFBHA
derivatives using GC/MS. The product results, along with the kinetics knowledge available in
the literataure, will be used to construct transformation mechanisms for 52 organic HPAPs that
contain carbon, hydrogen, or oxygen. Such explicit mechanisms will then be converted into
allomorphic/morphecule representations. In the meantime, an appropriately composed organic
HAPs mixture will be designed and prepared, and outdoor smog chamber experiments will be
conducted on the mixture and on individual components under simulated urban atmospheric
conditions. The chamber observational data will be used to study the behior of HAPs in an
urban-like environment and to evaluate the allomorphic transformation mechanisms. In addition,
the resesarchers will perform risk calculations using the new mechanistic data on precursor and
product HAPs for the purpose of comparing the potential cancer and noncancer risks of the
precursors and products. The risk calcuations will be used to guide the selection of HAPs and
their products for further experiments. The calculations will also help to identify transformed
species represented as reacting entities in the allomorphic mechanisms.

Expected Results:

The primary results of this study will be publications on the transformation
chemistry of important organic HAPs; the development of allomorphic mechanisms of HAP
formation and decay; and the conversion of conceptual chemistry into mathematical
representations that can be used in future air quality modeling. The primary benefit from these
results will be reduction in the uncertainty concerning atmospheric transformation of organic
HAPs, which can then be translated into more certain and realistic estimates of the human health
risks from HAPs. Another result be will be production of an optimized synthetic HAP mixture
well-suited for chamber testing, and a substantial observational data set from the UNC outdoor
smog chamber to be used to formulate and evaluate new reaction mechanisms for HAPs.
Another benefit will be a set of reaction mechanisms potentially useful for integrating HAPs
transformations into air quality models. This step will significantly help with regulatory
quantitative risk analysis and decision-making.

Progress and Final Reports:

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.